RU2667825C2 - Method and system for engine starting - Google Patents

Abstract

FIELD: engines and pumps.SUBSTANCE: present invention relates to methods and systems for improving starting of an engine. In one example, the method selects a first cylinder to receive fuel since engine stop in response to an intake valve of the cylinder being open and a position of the engine, allowing end of fuel injection to the cylinder a predetermined number of crankshaft degrees before intake valve closing of the cylinder.EFFECT: technical result is to improve the stability of engine starting.14 cl, 4 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to methods and systems for improving engine starting. The method may be particularly useful for engines that are operated using different types of fuel.

BACKGROUND AND SUMMARY OF THE INVENTION

It may be desirable, from the driver’s point of view, to start the engine to the idle speed as quickly as possible after the driver requests the engine to start. On the other hand, starting the engine up to idle can increase engine emissions as quickly as possible. Therefore, it may be desirable to provide an engine start that gives low emissions, while at the same time not prolonging the engine starting time so as not to disappoint the driver. However, injecting fuel into an arbitrary engine cylinder or simultaneously all engine cylinders at times can give partially desirable engine start results, meanwhile, sometimes causing disappointment with engine start results.

The inventors in the materials of this application have recognized the aforementioned disadvantages and have developed a method for starting the engine, comprising: selecting an engine cylinder for receiving a first fuel injection into the engine inlet after stopping the engine in response to the cylinder inlet valve being open and the engine position enabling the fuel injection to end cylinder for a predetermined number of degrees of the crankshaft angle before closing the cylinder inlet valve.

By selecting the engine cylinder for the first fuel injection event after the engine is stopped in response to the cylinder intake valve being open and the engine position allowing the fuel to be injected into the cylinder for a predetermined number of degrees of crankshaft rotation before closing the cylinder intake valve, it may be possible to provide a technical result of reducing engine emissions and cranking time of the engine. For example, fuel can be injected into the cylinder if the fuel injection can be completed early enough to allow the required amount of vaporized fuel and / or liquid fuel to enter the cylinder. Otherwise, fuel may be injected into another cylinder after the engine has turned to a position where the required amount of vaporized fuel may enter the cylinder.

According to one aspect of the invention, there is provided a method of starting an engine, the method comprising: selecting an engine cylinder for receiving a first fuel injection into an engine inlet after stopping the engine in response to an inlet valve of the cylinder being open and an engine position enabling fuel injection to end in the cylinder beyond a predetermined number of degrees of the crankshaft angle before closing the cylinder inlet valve.

According to an embodiment of the method, the cylinder is selected when the engine is stopped, and the duration of the fuel injection pulse increases as the position is closer to closing the cylinder inlet valve.

According to another embodiment of the method, the cylinder is selected when the engine is rotating.

According to another embodiment of the method, the end of the fuel injection is adjusted in response to the alcohol content of the fuel injected into the cylinder.

According to another embodiment of the method, the end of fuel injection is adjusted in response to engine temperature.

According to another embodiment of the method, a predetermined number of degrees of the crankshaft angle is adjusted in response to engine temperature.

According to another embodiment of the method, a predetermined number of degrees of the crankshaft angle is adjusted in response to the alcohol content of the fuel injected into the cylinder.

According to another embodiment of the aforementioned method, the end of the fuel injection is adjusted based on the closing moment of the cylinder inlet valve.

According to a second aspect of the invention, there is provided a method of starting an engine, comprising the steps of: selecting an engine cylinder for receiving a first fuel injection into an engine inlet after stopping an engine in response to an inlet valve of said cylinder being open and an engine stop position being greater than a predetermined the number of degrees of the angle of rotation of the crankshaft before closing the intake valve of said cylinder; and injecting fuel into another cylinder, the other cylinder receiving the first fuel injection into the engine inlet after stopping the engine in response to the inlet valve of said cylinder being open and the engine stopping position being less than a predetermined number of degrees of crankshaft rotation angle before closing the intake valve of said cylinder.

According to an embodiment of the aforementioned method, fuel is injected into another cylinder during an event of an open intake valve of another cylinder.

According to another embodiment of the method, the other cylinder is the first cylinder, which must have an open intake valve and a position to allow the end of fuel injection into the other cylinder for a predetermined number of degrees of crankshaft rotation angle before closing the intake valve of the other cylinder.

According to another embodiment, said method further comprises the step of injecting a first fuel injection into each remaining engine cylinder until the end of the cylinder stroke in response to the alcohol content of the fuel injected into the engine, which is larger than a predetermined value.

According to another embodiment, said method further comprises the step of injecting a first fuel injection into each of the remaining engine cylinders sequentially in the combustion order of the engine in response to the alcohol content of the fuel injected into the engine, which is less than a predetermined value.

According to another embodiment of the method, a predetermined number of degrees of the crankshaft angle before closing the intake valve is adjusted in response to barometric pressure.

According to a third aspect of the invention, there is provided an engine system comprising: an engine including a cylinder; an injection nozzle for injecting fuel into the cylinder; and a controller including constant commands for selecting a cylinder for the first combustion event in the cylinder after engine shutdown in response to the end of timing of fuel injection and the moment of closing of the intake valve.

According to an embodiment of the system, the timing of the end of the fuel injection timing is based on the alcohol content of the fuel injected into the engine.

According to another embodiment of the system, the timing of the end of the fuel injection timing is based on engine temperature.

According to another embodiment of the said system, teams select a cylinder additionally in response to the number of degrees of rotation of the crankshaft between the time at which the timing of the fuel injection ends and the moment of closing the intake valve, which is greater than the threshold number of degrees of the angle of rotation of the crankshaft.

According to another embodiment, said system further comprises additional commands for adjusting a threshold number of degrees of an angle of rotation of the crankshaft in response to the alcohol content of the fuel injected into the engine.

According to another embodiment, said system further comprises additional commands for adjusting a threshold number of degrees of an angle of rotation of the crankshaft in response to engine temperature.

The present description may provide several advantages. For example, an approach can improve engine starting stability by reducing the likelihood of misfire in the engine. In addition, the approach can improve emissions at engine start-up by avoiding arbitrary fuel supply to the engine cylinders. In addition, the approach can improve the perception of engine start by the driver.

The above advantages and other advantages and features of the present description will be readily apparent from the subsequent Detailed Description when considered alone or in connection with the accompanying drawings.

It should be clear that the essence of the invention given above is provided to introduce a simplified form of a selection of concepts that are further described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that accompany the detailed description. Moreover, the claimed subject matter is not limited to implementations that put an end to any of the disadvantages noted above or in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages described in the materials of this application will be more fully understood by reading an example of an embodiment indicated in the materials of this application as a Detailed Description when taken alone or with reference to the drawings, where:

FIG. 1 is a schematic diagram of an engine;

FIG. 2 and 3 are exemplary engine starting sequences; and

FIG. 4 is a flowchart of an example method for starting an engine.

DETAILED DESCRIPTION

The present description relates to starting the engine. The methods described herein can be used during hot or cold engine starts. In addition, the methods and systems described in the materials of this application are applicable to engines that operate exclusively on gasoline, alcohol or mixtures of gasoline and alcohol. FIG. 2 and 3 show exemplary engine starting sequences according to the method described in FIG. 4. The method of FIG. 4 provides for the start of fuel injection into the cylinder, while the inlet valve of the cylinder is open.

With reference to FIG. 1, an internal combustion engine 10 comprising a plurality of cylinders, one cylinder of which is shown in FIG. 1 is controlled by an electronic motor controller 12. The engine 10 includes a combustion chamber 30 and cylinder walls 32 with a piston 36 located therein and connected to the crankshaft 40. The starter engine 11 can selectively turn on and rotate the crankshaft 40 during engine start-up. The combustion chamber 30 is shown in communication with the intake manifold 44 and the exhaust manifold 48 through a respective intake valve 52 and exhaust valve 54. Each intake valve and exhaust valve may be actuated by the intake valve cam 51 and the exhaust valve cam 53. Alternatively, one or more of the inlet and outlet valves may be actuated by an electromechanically controlled valve coil and armature assembly. The position of the intake valve cam 51 may be detected by the intake valve cam sensor 55. The position of the exhaust cam 53 may be detected by the exhaust cam cam sensor 57. The setting of the distribution phases (for example, opening and closing) of the intake valves can be moved relative to the position of the crankshaft 40 using the cam indexing device 41. The setting of the distribution phases (for example, opening and closing) of the exhaust valves can be moved relative to the position of the crankshaft 40 using the cam indexing device 43.

A fuel injector 66 is shown disposed for injecting fuel into a cylinder 30, which is known to those skilled in the art as injection into an engine inlet. Fuel injector 66 delivers liquid fuel in proportion to the pulse width of the signal from controller 12. Fuel is supplied to fuel injector 66 by a fuel system (not shown) including a fuel tank, a fuel pump and a fuel rail (not shown). In addition, the intake manifold 44 is shown in communication with an optional electronic throttle 62, which adjusts the position of the throttle valve 64 to control the flow of air from the air intake 42 to the intake manifold 44.

An ignition system 88 without a distributor delivers an ignition spark to the combustion chamber 30 through the spark plug 92 in response to the action of the controller 12. A universal exhaust oxygen sensor (UEGO) 126 is shown connected to the exhaust manifold 48 upstream of the catalytic converter 70. Alternatively, a dual-mode exhaust oxygen sensor may be used in place of the UEGO sensor 126.

The exhaust gas converter 70, in one example, includes numerous catalyst briquettes. In yet another example, multiple emission control devices may be used, each with multiple briquettes. The exhaust gas catalyst 70, in one example, may be a ternary type catalyst.

Controller 12 is shown in FIG. 1 as a conventional microcomputer, including: a microprocessor unit 102, input / output ports 104, read-only memory 106, random access memory 108, standby memory 110, and a traditional data bus. The controller 12 is shown receiving various signals from sensors connected to the engine 10, in addition to those signals previously discussed, including: engine coolant temperature (ECT) from a temperature sensor 112 connected to the cooling pipe 114; a position sensor 134 coupled to the accelerator pedal 130 for sensing a force exerted by the foot 132; measuring the pressure in the intake manifold of the engine (MAP) from a pressure sensor 122 connected to the intake manifold 44; an engine position sensor from a Hall effect sensor 118 sensing the position of the crankshaft 40; measuring the mass of air entering the engine from the sensor 120; and measuring the position of the throttle from the sensor 58. The barometric pressure can also be read using the sensor 93 for processing by the controller 12. In a preferred aspect of the present description, the engine position sensor 118 generates a predetermined number of evenly spaced pulses every revolution of the crankshaft, from which the engine speed can be determined (RPM, in revolutions per minute).

In some examples, the engine may be coupled to an electric motor / battery system in a hybrid vehicle. A hybrid vehicle may have a parallel configuration, a serial configuration, or variants or combinations thereof. In addition, in some examples, other engine configurations may be used, for example, a V-shaped engine configuration.

During operation, each cylinder in the engine 10 typically undergoes a four-stroke cycle: the cycle includes an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. During the intake stroke, typically, the exhaust valve 54 closes and the intake valve 52 opens. Air is drawn into the combustion chamber 30 through the intake manifold 44, the piston 36 moves to the bottom of the cylinder so as to increase the volume inside the combustion chamber 30. The position in which the piston 36 is near the bottom of the cylinder and at the end of its stroke (for example, when the combustion chamber 30 is at its largest volume) is typically referred to by those skilled in the art as a lower dead point (BDC). During the compression stroke, inlet valve 52 and exhaust valve 54 are closed. The piston 36 moves towards the cylinder head in order to compress the air inside the combustion chamber 30. The point at which the piston 36 is at the end of its stroke and closest to the cylinder head (for example, when the combustion chamber 30 is at its smallest volume) is typically indicated by those skilled in the art as top dead center (TDC). In the process, hereinafter referred to as injection, fuel is introduced into the combustion chamber. In the process, hereinafter referred to as ignition, the injected fuel is ignited by a known ignition means, such as spark plug 92, resulting in combustion. During the expansion stroke, expanding gases push the piston 36 back to the BDC. The crankshaft 40 converts the movement of the piston into the torque of the rotating shaft. Finally, during the exhaust stroke, the exhaust valve 54 opens to discharge the combusted fuel-air mixture to the exhaust manifold 48, and the piston returns to the TDC. Note that the above is merely shown as an example, and that the settings for opening and / or closing the inlet and outlet valves can be changed so as to give positive or negative valve closure, late closing of the inlet valve, or various other examples.

Thus, the system of FIG. 1 provides an engine system comprising: an engine including a cylinder; an injection nozzle for injecting fuel into the cylinder; and a controller including constant commands for selecting a cylinder for the first combustion event in the cylinder after engine shutdown in response to the end of timing of fuel injection and the moment of closing of the intake valve. The engine system includes those cases when the timing of the fuel injection timing is based on the alcohol content of the fuel injected into the engine. The engine system includes those cases where the timing of the fuel injection timing is based on the temperature of the engine. The engine system also includes cases where teams will select a cylinder additionally in response to the number of degrees of rotation of the crankshaft between the timing of the timing of the fuel injection and the moment the intake valve closes, which is greater than the threshold number of degrees of the angle of rotation of the crankshaft. The engine system further comprises additional commands for adjusting the threshold number of degrees of the crankshaft angle in response to the alcohol content of the fuel injected into the engine. The engine system additionally contains additional commands for adjusting the threshold number of degrees of the crankshaft angle in response to engine temperature, manifold absolute pressure (MAP), and crankshaft speed.

Next, with reference to FIG. 2, a first example of a simulated engine start sequence is shown. The sequence of FIG. 2 may be provided by the method of FIG. 4 in the system of FIG. 1. The vertical marks at time points T1 and T2 show the time points of interest during the sequence.

FIG. 2 includes four cylinder cycle graphs for a four-cylinder engine having a cylinder order of 1-3-4-2. The cylinder strokes of cylinder number one are on a graph that has a Y axis labeled Cylinder 1 (CYL 1). Similarly, cylinder strokes for the remaining cylinders 2-4 are marked similarly. The X axis represents the position of the engine during the engine start sequence. The time for the engine to go through each cycle varies depending on the number of engine revolutions, but the intervals of cycles (for example, 180 degrees of the crankshaft rotation angle) are always the same. Thus, the time intervals may be longer for the first pair of cylinder strokes during cranking, but the time between cylinder strokes decreases as the engine speed rises. The X axis of the measure of each cylinder is marked to indicate the existing measure in which each cylinder is located at some point in time. For example, the sequence begins on the left side of the figure with cylinder number one in the intake stroke and continues to move to the right side of the figure. At the same time, cylinder number three is in the exhaust stroke, cylinder number four is in the expansion stroke, and cylinder number two is in the compression stroke.

The settings for the inlet valve opening timing for each of the four cylinders are indicated by wide lines above each cylinder stroke. For example, line 200 represents the inlet valve opening time for cylinder number one. The inlet valve opens near the top dead center of the intake stroke and closes after the bottom dead center of the compression stroke. Similar valve timing characteristics are shown for cylinders 2-4. The ignition timing for each cylinder is represented by *, such as shown in 202. The fuel injection end times (EOIs) are indicated by the symbols marked 203.

The fifth graph from above in FIG. 2 shows the engine speed depending on the position of the engine. The Y axis represents the engine speed and the engine speed increases in the direction of the arrow of the Y axis. The X axis represents the engine position and the engine position is the same engine position as shown for graphs 1-4.

The sequence starts at time T0, where the engine decelerates to zero speed. The engine can be stopped in response to a request from the driver or in response to an automatic engine stop initiated by the controller. Fuel and sparks are not delivered to the engine cylinders, while the engine speed drops to zero at time T1. The engine speed decays from time T0 to time T1, and the intake valves of the respective cylinders continue to operate. The position of the engine can be monitored, while the engine speed approaches zero, so that the position of the engine is known at the time of starting the engine.

At time T1, the engine becomes completely stopped and awaits a request to start the engine. The engine can be stopped at time T1 for a short or long period of time; however, the length of time that the engine is stopped is not reflected on the X axis of any of the five graphs, since the X axis of each graph is based on the position of the engine. The engine start request can be initiated using a driver or controller that automatically starts the engine without giving the driver an input signal to a device that has the sole purpose of starting and / or stopping the engine (for example, an ignition switch).

Upon receipt of a request to start the engine, fuel is injected into cylinder four, while cylinder number four is in the intake stroke and while the inlet valve of cylinder number four is open. In this example, fuel is injected into the cylinder inlet at time 203, and fuel injection is completed before the engine starts to rotate in response to a request to start the engine. The engine starts to rotate with the starter after the first fuel injection event has been completed. The fuel injected at time 203 is for the first combustion event after the engine is stopped. Fuel is injected into the cylinder number four for the first time after the engine stopped at time T1, since the inlet valve of the cylinder number four is open, and since the end of the fuel injection time into the cylinder is greater than a predetermined number of degrees of crankshaft rotation to intake valve closing moment (IVC). The predetermined number of degrees of the crankshaft angle is less than the number of degrees of the angle of rotation of the crankshaft shown at time 204. The predetermined number of degrees of the angle of rotation of the crankshaft shown at time 204 can be adjusted in response to temperature, engine speed, MAP and the number of alcohol in the fuel injected into the cylinder.

At time T2, the second fuel injection ends after the engine is stopped. Fuel is injected into the inlet of cylinder number two. Thus, the engine is started by sequentially dispensing fuel to each cylinder according to the operating order of the engine cylinders. The second fuel injection and subsequent fuel injections into other cylinders occur during the time when the intake valves of the cylinders receiving the fuel are closed. By injecting fuel into the intake ports of the cylinders, while the intake valves of the cylinder receiving the fuel are closed (for example, during the exhaust stroke of the cylinder) after the first injection to the open valve, the injected fuel may have a longer time for evaporation, and air and fuel are mixed may improve since the speed of the mixture through the inlet valve during the opening of the inlet valve may be high. Therefore, the increase in the number of revolutions and engine emissions can be improved. The engine rotates at the number of revolutions of cranking the crankshaft at time T2.

At time T3, the first fuel injection at 203 is ignited by a spark, and the engine starts to accelerate. The fuel injection for the second combustion event of cylinder number four after engine shutdown occurs during the time of the closed intake valve of cylinder number four. In this way, cylinder number four switches from injection to an open valve to injection to a closed valve. Injection on an open valve can reduce engine start-up time, and injection on a closed valve can improve engine emissions. Injection into each of the other cylinders is a sequential injection of fuel into a closed valve according to the order of operation of the engine cylinders after time T3.

Thus, if the engine is stopped in a position where fuel can be injected into the cylinder having the intake valve open and the fuel injection for the first combustion event can be stopped before the engine is within a predetermined number of degrees of the crankshaft angle to the cylinder IVC, receiving fuel, fuel is injected into the cylinder, which is beyond a predetermined number of degrees of the crankshaft angle to IVC. By injecting fuel into an open valve, the engine starting time can be shortened, and injecting fuel into an open intake valve, which occurs beyond a predetermined number of degrees of crankshaft angle from the IVC, allows the injected fuel to vaporize, thereby reducing the chance of misfiring in the engine.

Next, with reference to FIG. 3, a second exemplary engine starting sequence is provided. The engine start sequence in FIG. 3 is similar to the start sequence in FIG. 2. In addition, the graphs of FIG. 3 are similar to the graphs of FIG. 2. Therefore, the description of the individual graphs of FIG. 3 is omitted for brevity, and the description in FIG. 2 applies to FIG. 3 except as indicated below. The sequence of FIG. 3 may also be performed by the method of FIG. 4 in the system of FIG. one.

At time T10, the engine decelerates to zero speed. The engine slows down in response to a request to stop the engine. The spark and fuel supplied to the engine cylinders are taken out of operation while the engine slows down. The engine stops completely at time T11.

At T11, the engine stops until a request to start the engine is made. The engine shutdown time can be long or short. In some examples, the engine starts automatically without the driver engaging the ignition switch. The engine is stopped in a position where the inlet valve opening duration 304 to IVC is less than the threshold duration. In other words, the number of degrees of the crankshaft angle between the engine stop position and the IVC for cylinder number four is less than the threshold number of degrees of the crankshaft angle. Other engine cylinders do not have an inlet valve open at time T11.

The engine start request is received after the engine has been stopped and the engine starts to rotate using the engine starter. Fuel is not injected into the inlet of cylinder number four, as the engine was stopped for less than a predetermined number of degrees of crankshaft angle to cylinder number IVC. If fuel were to be injected into the inlet of cylinder number four while the inlet valve was open, the engine could ignite, since less than the required amount of injected fuel could enter the cylinder, since the EOI would be for less than a predetermined number of degrees of crankshaft angle to IVC. Therefore, fuel injection into the inlet channel of cylinder number four is avoided for the first combustion event after engine shutdown.

At time T12, the first fuel injection after the engine stops. Fuel is injected onto the open valve of cylinder number two, because cylinder number two is the first cylinder of the engine where the EOI is possible, while the inlet valve of the cylinder receiving fuel is open, and where the EOI is beyond a greater than a predetermined number of degrees of rotation of the crankshaft angle shaft from the IVC cylinder receiving fuel. The second fuel injection after stopping the engine is performed in cylinder number one during the time when the intake valve of cylinder number one is closed. Fuel is sequentially injected into other cylinders based on the combustion order in the engine, while the intake valves of the cylinders receiving fuel are closed.

At time T13, a spark is supplied to cylinder number two, and the first amount of injected fuel is burned after the engine is stopped. A spark triggers a combustion event, and the engine rpm accelerates from the number of revolutions of crankshaft rotation in response to combustion in cylinder number two. The engine ramps up to idle after the first combustion event.

Thus, if the engine is stopped in a position where the EOI for the cylinder having the inlet valve open is or would have been less than a predetermined number of degrees of crankshaft angle to IVC, fuel is injected onto the inlet valve of the cylinder, following in cylinder order engine. Fuel is injected at a point in time where the EOI for the cylinder receiving fuel is beyond a predetermined number of degrees of crankshaft angle to IVC while the intake valve of the cylinder receiving fuel is open. Thus, it is possible to inject fuel into a cylinder having an open intake valve up to an EOI that is less than a predetermined number of degrees of the crankshaft angle from IVC.

Next, with reference to FIG. 4, a method for starting a stopped engine is shown. The method of FIG. 4 can be applied to the system of FIG. 1. The method of FIG. 4 may include the operating sequences shown in FIG. 2 and 3. Additionally, the method of FIG. 4 may be stored as executable instructions in the controller memory, as shown in FIG. one.

At 402, method 400 evaluates whether or not engine start has been requested. Starting the engine may be requested by the driver actuating the lock or ignition button. Alternatively, engine start may be requested by a controller that automatically restarts the engine in response to vehicle operating conditions. If method 400 determines that an engine start request is present, method 400 proceeds to step 404. Otherwise, method 400 proceeds to exit.

At 404, method 400 determines the alcohol content of the fuel injected into the engine using an injection nozzle into the inlet. The fuel alcohol content can be determined using a fuel sensor or an exhaust gas oxygen sensor and the amount of fuel injected into the engine. In some examples, the alcohol content of the injected fuel may be determined before the engine is stopped. A certain alcohol content can be stored in memory, from where it can be extracted during engine start-up. Method 400 proceeds to step 406 after the fuel alcohol content is determined.

At step 406, method 400 determines the temperature of the engine. Engine temperature can be determined by the temperature of the engine coolant or by the temperature of the cylinder head of the engine. The engine temperature gives an indication as to whether or not the injected fuel will evaporate to the required degree in the inlet of the engine cylinder during engine start-up. Method 400 proceeds to step 408 after the engine temperature is determined.

At step 408, method 400 determines the desired EOI based on engine temperature, MAP, and the alcohol content of the fuel injected into the engine. EOI is determined by the engine temperature, MAP and the alcohol content of the injected fuel, since the engine temperature, MAP and the fuel alcohol content affect the air charge and fuel evaporation, thereby affecting the required fuel mass and the amount of fuel that can enter the cylinder before IVC.

In one example, the EOI is determined empirically by performing engine starts, where the EOI is adjusted in response to the fuel alcohol content and engine coolant temperature. The number of degrees of the crankshaft angle between the EOI and IVC of the fuel receiving cylinder increases as the alcohol content of the injected fuel increases, since the alcohol may not evaporate as well as gasoline. In addition, the injection pulse duration may increase as the proportion of alcohol increases. In some cases, the interval from EOI to IVC increases, and at the same time, the duration of the injection pulse increases as the proportion of alcohol increases. In other cases, only the EOI or pulse width changes. On the other hand, the number of degrees of the crankshaft angle between the EOI and IVC of the cylinder receiving the fuel decreases as the alcohol content of the fuel decreases. Similarly, the number of degrees of the crankshaft angle between the EOI and IVC of the cylinder receiving the fuel increases, and the pulse duration of the fuel injection can increase as the temperature of the engine decreases, since the fuel may not evaporate, for a given fraction of alcohol, it’s also good as required at lower engine temperatures. The number of degrees of the crankshaft angle between EOI and IVC, and the injection pulse duration of the cylinder receiving the fuel, decreases as the engine temperature rises, since the fuel can evaporate well at higher engine temperatures. In one example, the basic EOI and fuel pulse duration for the first cylinder receiving fuel, after the engine is stopped, are beyond a predetermined number of degrees of the crankshaft angle to IVC. The basic EOI and pulse duration are based on the injection of gasoline into the engine at 20 ° C. Engine coolant temperature and fuel alcohol content are indexed by tables that provide terms or factors that modify the basic EOI and fuel pulse duration. The basic EOI and the pulse width value are adjusted, and the method 400 proceeds to step 410.

At step 410, method 400 adjusts the EOI and fuel pulse duration (as the IVC acts on the trapped air charge) based on the position of the piston relative to the IVC for the cylinder receiving the first fuel injection after the engine stops. In some examples, the IVC may be adjusted to different positions relative to the position of the crankshaft during engine start-up based on engine temperature, alcohol content of the injected fuel, and other conditions. Therefore, the position of the IVC relative to the position of the engine piston may vary. The position of the piston when the engine is stopped relative to the top dead center of the intake stroke and IVC, or, alternatively, relative to the bottom dead center of the intake stroke and IVC, can be the basis for further adjusting the EOI and fuel pulse duration. For example, if the IVC is delayed (for example, shifted closer to TDC) later than the bottom dead center of the intake stroke, where the piston begins to compress the contents of the cylinder, the EOI can more likely stick to a predetermined number of degrees of crankshaft rotation to the bottom dead center of the intake stroke than with respect to the IVC . On the other hand, if the IVC is advanced (e.g., shifted closer to the BDC), the EOI may be advanced by the same or a different number of degrees. Leading the EOI relative to the IVC, that is, increasing the spacing of the crankshaft between the EOI and the IVC, may allow the fuel to completely vaporize to the IVC. If the IVC is delayed from the bottom dead center of the intake stroke, the EOI may be delayed further, since the gap in the angle of rotation of the crankshaft from EOI to IVC will increase to constantly set the EOI moment. If the IVC is advanced from the bottom dead center of the intake stroke, the EOI can be advanced by a similar number of degrees to maintain a similar gap from the EOI to the IVC. In some engines or combustion chambers, at the engine crankshaft speed, the interval from EOI to BDC can determine the proportion of injection on the open valve of the injected fuel to the fuel transferred from the inlet to the cylinder as a function of ECT and the type of fuel during restart when stop / start. In other engines, the span from EOI to IVC may be more predominant. In one example, settings for EOI are determined empirically and stored in tables and functions. Tables and / or functions are indexed using IVC in degrees of the crankshaft angle. The tables output a term or factor that are added to or multiply the EOI moment setting. Thus, the EOI torque setting is adjusted based on the IVC and piston position at the IVC. Method 400 proceeds to step 412 after the EOI is configured.

At step 412, method 400 evaluates whether or not motor rotation is required to determine the position of the engine. If the position of the engine is known before cranking the engine, the answer is no, and method 400 proceeds to step 416. Otherwise, the answer is yes, and method 400 proceeds to step 414.

At step 414, method 400 begins to rotate the engine using a starter motor or an electric motor that can provide torque to the drive to the drive wheels of the vehicle. The engine position sensors provide signals by which the position of the engine can be determined as the engine rotates. For example, the position of the engine can be determined from the position sensors of the crankshaft and camshaft. The method 400 proceeds to step 416 after the position of the engine is determined.

At step 416, method 400 selects a first engine cylinder having an open intake valve, where closing the intake valve (IVC) is through a greater than a threshold number of degrees of crankshaft angle after fuel injection (EOI) is completed. The threshold number of degrees of the crankshaft angle can be adjusted to the alcohol content in the injected fuel and the engine temperature. In one example, the threshold value is a base value that is at a predetermined number of degrees of the crankshaft angle between the EOI and IVC. Tables and / or functions are indexed using the alcohol concentration of the injected fuel and engine temperature. Tables and / or functions output terms or factors that are added to or multiplied by the base value to give a customized threshold value. In one example, the threshold value rises as the alcohol content of the injected fuel increases, so that a greater number of degrees of the crankshaft angle is between the EOI and the IVC. The threshold value decreases as the alcohol content of the injected fuel increases. The threshold value decreases as the engine temperature rises. The threshold value rises as the engine temperature rises.

In some examples, the threshold value may also be adjusted to take into account barometric pressure, engine cranking speed and ambient humidity. For example, if the barometric pressure decreases, the threshold value may decrease, since the injected fuel can more easily evaporate. If the barometric pressure rises, the threshold value may rise, since the injected fuel cannot evaporate as easily. If the engine crankshaft rpm rises above the base crankshaft rpm, the threshold may increase because a faster engine crankshaft rpm can give less time for the injected fuel to evaporate. If the ambient humidity rises above baseline humidity, the threshold value may rise, since the injected fuel cannot evaporate just as easily.

Thus, additional time may be allowed for the fuel to evaporate from the cylinder inlet for the first fuel injection event after the engine is stopped, so that misfire in the engine can be avoided. The method 400 proceeds to step 418 after the first cylinder is selected to receive the injected fuel into the fuel inlet after stopping the engine.

At 418, method 400 judges whether or not fuel should be injected while the engine is spinning. In one example, the answer is yes, and method 400 proceeds to step 430, when the position of the engine may not be set until the engine rotates. If the position of the engine can be set before the engine rotates, the answer is no, and method 400 proceeds to step 420.

In step 420, method 400 injects fuel into the inlet of the cylinder selected in step 416. Fuel is injected by dispensing fuel under pressure to the fuel injector and opening the fuel injector using an electrical signal. Method 400 proceeds to step 422 after fuel is injected.

At 422, method 400 rotates the engine. The engine can be rotated with a starter or with an electric motor that can supply torque to drive the vehicle. Method 400 proceeds to 434 after the engine begins to rotate.

At step 430, method 400 rotates the engine, as described at step 422. Method 400 proceeds to step 432 after the engine starts to rotate.

At step 432, method 400 injects fuel as described at 420. Method 400 proceeds to step 434 after the engine starts to rotate.

At step 434, method 400 evaluates whether or not the alcohol content of the fuel injected into the engine is greater than a threshold value. If so, method 400 proceeds to step 440. Otherwise, the answer is no, and method 400 proceeds to step 436.

At step 436, method 400 injects fuel into each cylinder of the engine after fuel is injected into the first cylinder after the engine is stopped. Fuel is injected into each cylinder sequentially, according to the operating order of the engine cylinders, and as shown in FIG. 2 and 3. Fuel is injected into the cylinders when the intake valves of the cylinders receiving the fuel are closed (for example, during a cylinder exhaust stroke). In this way, fuel is injected into the engine onto an open intake valve for a first combustion event, and then subsequent fuel injections occur during closed intake valves. Method 400 proceeds to exit after sequential fuel injection is started.

At step 440, method 400 injects fuel into all engine cylinders until the end of the first exhaust stroke of the first fuel receiving cylinder. In some examples, fuel is injected into all cylinders simultaneously. By injecting fuel into all cylinders until the end of the first exhaust stroke of the first cylinder receiving fuel, it may be possible to improve fuel evaporation for the remaining engine cylinders. Fuel can be injected into all cylinders as the alcohol concentration of the injected fuel increases, so that alcohol fuels have a longer time to evaporate before entering the engine cylinders. After simultaneously injecting fuel into all cylinders with the exception of the first cylinder receiving fuel, fuel is sequentially injected into the cylinders. Method 400 proceeds to exit after fuel is injected into all cylinders.

Thus, the method of FIG. 4 provides a method for starting an engine, comprising: selecting an engine cylinder for receiving a first fuel injection into an engine inlet after stopping the engine in response to an inlet valve of the cylinder and the engine position being open, allowing the injection of fuel into the cylinder to end for a predetermined number of degrees of crank angle shaft before closing the cylinder inlet valve. The method includes those cases where the cylinder is selected when the engine is stopped, and where the duration of the fuel injection pulse increases as the position is closer to closing the cylinder inlet valve. The method includes those cases when the cylinder is selected when the engine is rotating. The method includes those cases where the end of the fuel injection is adjusted in response to the alcohol content of the fuel injected into the cylinder.

In some example, the method includes those cases where the end of the fuel injection is adjusted in response to engine temperature. The method includes those cases where a predetermined number of degrees of the crankshaft angle is adjusted in response to engine temperature. The method includes those cases when a predetermined number of degrees of the crankshaft angle is adjusted in response to the alcohol content of the fuel injected into the cylinder. The method also includes those cases where the end of the fuel injection is adjusted based on the moment the cylinder inlet valve closes.

In yet another example, the method of FIG. 4 provides a method for starting an engine, the method comprising: selecting a cylinder for receiving a first fuel injection into an engine inlet after stopping the engine in response to the cylinder inlet valve being open and the engine stopping position being greater than a predetermined number of degrees of crankshaft rotation to closing the inlet valve of the cylinder; and injecting fuel into another cylinder, the other cylinder receives the first fuel injection into the engine inlet after stopping the engine in response to the cylinder inlet valve being open and the engine stopping position being less than a predetermined number of degrees of the crankshaft rotation angle before closing the cylinder intake valve .

In some examples, the method includes cases where fuel is injected into another cylinder during an open intake valve event of the other cylinder. The method also includes those cases where the other cylinder is the first cylinder to obtain an open intake valve and position to allow the injection of fuel into the other cylinder to end at a predetermined number of degrees of crankshaft rotation angle before closing the intake valve of the other cylinder. The method further comprises injecting a first fuel injection into each remaining engine cylinder until the end of the cylinder exhaust stroke in response to the alcohol content of the fuel injected into the engine, which is larger than a predetermined value. The method further comprises injecting a first fuel injection into each of the remaining engine cylinders sequentially in the combustion order of the engine in response to the alcohol content of the fuel injected into the engine, which is less than a predetermined value. The method includes those cases where a predetermined number of degrees of the crankshaft angle before closing the intake valve is adjusted in response to barometric pressure.

As will be appreciated by one of ordinary skill in the art, the method described in FIG. 4 may be one or more of any number of processing strategies, such as event driven, interrupt driven, multitasking, multithreaded, and the like. As such, the various illustrated steps or functions may be performed in the illustrated sequence, in parallel, or in some cases skipped. Similarly, the processing order is not necessarily required to achieve the objectives, features and advantages described in the materials of this application, but is provided to facilitate illustration and description. Although not explicitly illustrated, one of ordinary skill in the art will recognize that one or more of the illustrated steps or functions may be performed multiple times, depending on the particular strategy used. In addition, the described actions, operations, methods and / or functions may graphically represent a control program that must be programmed into the read-only memory of a machine-readable storage medium in an engine control system.

This completes the description. Reading it by experts in the field of technology would recall many changes and modifications without leaving the essence and scope of the description. For example, power drives with a fully electric or partially electric drive could advantageously use the present description. In addition, the system and methods described herein may advantageously be used with various engine configurations, not limited to engine configurations I4, V6, V8, V10, V12 and I6.

Claims (16)

1. The method of starting the engine, comprising the stage of: selecting a cylinder for receiving the first fuel injection into the engine inlet after stopping the engine in response to the cylinder inlet valve being open and the engine position allowing the injection of fuel into the cylinder to end in a predetermined number of degrees angle of rotation of the crankshaft before closing the intake valve of the cylinder. 2. The method according to claim 1, in which the cylinder is selected when the engine is stopped and in which the pulse duration of the fuel injection increases as the position is closer to closing the intake valve of the cylinder. 3. The method according to claim 1, wherein the cylinder is selected when the engine is rotating. 4. The method according to claim 1, in which the end of the fuel injection is configured in response to the alcohol content of the fuel injected into the cylinder. 5. The method according to claim 1, in which the end of the fuel injection is configured in response to engine temperature. 6. The method of claim 1, wherein the predetermined number of degrees of the crankshaft angle is adjusted in response to engine temperature. 7. The method according to p. 1, in which a predetermined number of degrees of the angle of rotation of the crankshaft is adjusted in response to the alcohol content of the fuel injected into the cylinder. 8. The method according to p. 1, in which the end of the fuel injection is configured based on the moment of closing the intake valve of the cylinder. 9. A method for starting an engine, comprising the steps of: selecting an engine cylinder for receiving a first injection of fuel into the engine inlet after stopping the engine in response to the inlet valve of said cylinder being open and the engine stop position being greater than a predetermined number of degrees of crankshaft rotation angle before closing the inlet valve of said cylinder; and fuel is injected into another cylinder, the other cylinder receiving the first fuel injection into the engine inlet after stopping the engine in response to the inlet valve of said cylinder being open and the engine stopping position being less than a predetermined number of degrees of crankshaft rotation angle before closing the intake valve mentioned cylinder. 10. The method of claim 9, wherein the injection of fuel into another cylinder occurs during an event of an open intake valve of the other cylinder. 11. The method according to p. 9, in which the other cylinder is the first cylinder, which must have an open intake valve and a position to allow the end of fuel injection into another cylinder for a predetermined number of degrees of crankshaft rotation angle before closing the intake valve of the other cylinder. 12. The method according to claim 9, further comprising the step of injecting a first fuel injection into each remaining engine cylinder until the end of the cylinder exhaust stroke in response to the alcohol content of the fuel injected into the engine, which is larger than a predetermined value. 13. The method according to p. 12, further comprising the step of injecting a first fuel injection into each of the remaining engine cylinders sequentially in the combustion order of the engine in response to the alcohol content of the fuel injected into the engine, which is less than a predetermined value. 14. The method according to p. 9, in which a predetermined number of degrees of the angle of rotation of the crankshaft before closing the intake valve is adjusted in response to barometric pressure.

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